Nick has already writted a proposal in torspec/ideas for what we need to do to remove this

2) RSA-1024

This is not an immediate concern as each relay also uses an Ed25519 key

We should remove RSA and use only Ed25519 keys.

Scariest places we use RSA: old hidden services, followed by signed documents. everything relays sign is with ed and rsa keys, so we don't need to worry much about rsa here

Tor currently doesn't support relays without RSA keys. We would need to make it such that a correct descriptor has an ed25519 key, and remove all the places where RSA is currently used. This might be ideal to save on bandwidth.

We use a hash of the RSA identity key all over the code for relay identity.

3) Sha-1

We use this in relay fingerprints and old hidden services

4) DH 1024

5) TAP - constructed out of the above things. TAP is part of the old onion service protocol.
When we get rid of TAP, we'll get rid of DH 1024.

We can remove TAP when we remove support for old onion services. Deprecating TAP is desirable but hard because of rendezvous points.